Materials operable to withstand high energy impacts from various sources, such as projectiles and blast compression waves, find use in a wide range of applications, including civilian and military structural reinforcement applications and armored vehicle applications. Ceramic plates and reinforced composite materials, for example, have been used to shield vehicles from potential damage caused by various explosive devices. Predicting which materials will exhibit desirable properties for use in ballistic applications is notoriously difficult, however.
Glass fibers have been used to reinforce various polymeric resins for many years. Some commonly used glass compositions for use in reinforcement applications include the “E-glass” and “D-glass” families of compositions. Another commonly used glass composition is commercially available from AGY (Aiken, S.C.) under the trade name “S-2 Glass.” However, reinforcing polymeric resins with glass fibers for high energy impact applications such as ballistic or blast resistance applications does not necessarily result in composites having other desirable mechanical properties as well.
In general, glass fibers can be produced from small streams of molten glass extruded through small orifices located in a bushing. The fibers of molten glass which issue from the bushing are attenuated to a desired diameter by pulling the fibers until the desired diameter is achieved, during which time the fibers cool and solidify. These cooled fibers or filaments can then be coated with a sizing that can impart desired properties. As used herein, the term “sizing” refers to a coating composition applied to fiber glass filaments immediately after forming, and the term may be used interchangeably with the terms “size,” “sizing composition,” “primary sizing,” “binder composition,” and “binder.” After their formation and treatment, the sized glass fibers can be gathered into bundles or strands comprising a plurality of individual fibers. Similarly, bundles or strands can be further gathered into rovings comprising a plurality of bundles or strands. Continuous strands or rovings can be wound upon a spool to form a package. Lengths of strands or rovings can then be dispensed from the spool as needed.